SIDNEY, Neb. — Record-breaking cold swept across western Nebraska over the weekend as an arctic air mass pushed daily low temperatures to historic levels, according to the National Weather Service.

New daily record lows were set Saturday morning in Alliance, Sidney, Chadron and Laramie, Wyo. Alliance recorded the coldest temperature at minus 26 degrees, breaking the previous record of minus 24 set in 1950. Sidney dropped to minus 15, surpassing the old record of minus 13 from 1949. Chadron fell to minus 21, breaking a 1949 record, while Laramie set a new daily record low of minus 13.

North Platte tied its daily record low on Sunday, reaching minus 14 degrees, a mark originally set in 1950.

Extreme wind chills accompanied the cold temperatures across the region. The lowest reported wind chill was minus 35 degrees near Hay Springs early Saturday morning. Multiple locations across western and north-central Nebraska reported wind chills ranging from minus 24 to minus 32 degrees, including Whitman, Gordon, Brule, Halsey and Oshkosh.

The National Weather Service said the prolonged cold was caused by a deep arctic air mass that settled over the central Plains. Forecasters expect the cold spell to end Monday as milder air moves into the region from the west.